Civil Rights
Movements, leaders, victories and the continuing fight for equality.
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THE BHP WIRE —
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Explore the people, places, events, achievements, struggles and stories that shaped our journey.
Movements, leaders, victories and the continuing fight for equality.
Innovation, patents, science, technology and world-changing contributions.
Pioneers, champions, Negro Leagues, records, activism and excellence.
Meet the people whose lives, choices and achievements shaped the journey.
Black towns, communities, institutions and places where history happened.
Moments that changed communities, movements, institutions and the nation.
Mansa Musa was the ruler of the Mali Empire in West Africa. Details recorded here should be sourced; unknown information is left blank.
MORE →Reflects the personal views, recollections, and perspective of the author, Mike Davis.
This is a personal recollection on the Move fire on May 13, 1985
A killer T cell (also known as TC, cytotoxic T lymphocyte, CTL, T-killer cell, cytolytic T cell, CD8+ T-cell or cd8) is a T lymphocyte (a type of white blood cell) that kills cancer cells, cells that are infected by intracellular pathogens such as viruses or bacteria, or cells that are damaged in other ways. Most cytotoxic T cells express T-cell receptors (TCRs) that can recognize a specific antigen. An antigen is a molecule capable of stimulating an immune response and is often produced by cancer cells, viruses, bacteria or intracellular signals. Antigens inside a cell are bound to class I MHC molecules, and brought to the surface of the cell by the class I MHC molecule, where they can be recognized by the T cell. If the TCR is specific for that antigen, it binds to the complex of the class I MHC molecule and the antigen, and the T cell destroys the cell. In order for the TCR to bind to the class I MHC molecule, the former must be accompanied by a glycoprotein called CD8, which binds to the constant portion of the class I MHC molecule. Therefore, these T cells are called CD8+ T cells. The affinity between CD8 and the MHC molecule keeps the TC cell and the target cell bound closely together during antigen-specific activation. CD8+ T cells are recognized as TC cells once they become activated and are generally classified as having a pre-defined cytotoxic role within the immune system. However, CD8+ T cells also have the ability to make some cytokines, such as TNF-α and IFN-γ, with antitumour and antimicrobial effects.
Cytotoxic T-lymphocyte associated protein 4, (CTLA-4) also known as CD152 (cluster of differentiation 152), is a protein receptor that functions as an immune checkpoint and downregulates immune responses. CTLA-4 is constitutively expressed in regulatory T cells but only upregulated in conventional T cells after activation – a phenomenon which is particularly notable in cancers. It acts as an "off" switch when bound to CD80 or CD86 on the surface of antigen-presenting cells. It is encoded by the CTLA4 gene in humans, and by the Ctla4 gene in mice.
Cytotoxicity refers to the capacity of a substance or agent to damage or kill living cells, reflecting a critical parameter in pharmacology, toxicology, and biomedicine. It is distinct from cytostatic effects, which inhibit cell growth and proliferation without causing cell death. Cytotoxic agents can induce a range of cellular responses, including inhibition of cell growth, induction of apoptotic or necrotic cell death, and disruption of metabolic or structural cellular integrity. Assessing cytotoxicity is fundamental for evaluating the safety and efficacy of pharmaceutical compounds, chemicals, and biomaterials, as it helps predict potential adverse effects and guides therapeutic development. Various assays—based on enzyme activity, membrane permeability, metabolic activity, or cell proliferation—are routinely employed to characterize and quantify cytotoxic effects in vitro, providing essential insights into cell viability and the mechanisms underlying toxic responses.
Within the scientific discipline of toxicology, Cytotoxic T lymphocytes (CTLs) are generated by immune activation of cytotoxic T cells (Tc cells). They are generally CD8+, which makes them MHC class I restricted. CTLs are able to eliminate most cells in the body since most nucleated cells express class I MHC molecules. The CTL-mediated immune system can be divided into two phases. In the first phase, functional effector CTLs are generated from naive Tc cells through activation and differentiation. In the second phase, affector CTLs destroy target cells by recognizing the antigen-MHC class I complex.
Before the 1921 destruction of Tulsa’s Greenwood District, Black residents had created a remarkable center of business and community life. The district included stores, professional offices, entertainment venues and homes owned by Black citizens. Understanding Greenwood means learning what was built—not only what was burned.
MORE →Shirley Chisholm, elected in 1968.